The Islanders (42-24-7, 91 points) were shut out on home ice on Tuesday, suffering a 5-0 loss to the Bruins. New York managed only a season-low 13 shots in the game.
The defeat dropped New York two points behind the Capitals for first place in the Metropolitan Division, and also narrowed the gap between the Islanders and the Penguins (89 points), Hurricanes (87) and Blue Jackets (84).
With just nine games remaining in the regular season, the Islanders don't have time to dwell on the tough result.
"(Tuesday) obviously wasn't to the level that we've set for ourselves," forward Josh Bailey said. "Unfortunately in an 82-game season those things happen. It doesn't make it acceptable by any means. I think if anything you just need to talk about it, learn from it, and turn the page and still remember that we do have a good, quality team in here."
New York suffered a blow on Wednesday when it learned center Valtteri Filppula is expected to miss four weeks with an upper-body injury.
Filppula, 35, was injured in the first period Tuesday night on a hit from behind by Boston Bruins defenseman Connor Clifton. Filppula has 29 points (15 goals, 14 assists) in 71 games in his first season with the Islanders.
Meanwhile, the Canadiens also can't rest on their laurels in the wake of their 3-1 win over the Flyers on Tuesday. Montreal (38-28-7, 83 points) sits just a point behind the Blue Jackets for the final Eastern Conference wild-card berth.
"Our focus right now is really trying to emphasize controlling what we can control," forward Brendan Gallagher said. "We did a good job tonight but now we've got to move on. It's kind of the position we're in, we've got to put together some wins. ... We need every game badly right now."
New York has been one of the NHL's best defensive teams this season, creating added pressure on the Canadiens to break out of their scoring slump. Montreal has scored just 15 goals over their last eight games, which has unsurprisingly led to just a 3-5-0 record in that stretch.
The lack of offense has obscured more outstanding play from Carey Price, who is expected to make his sixth consecutive start on Thursday. Montreal's star netminder has a .948 save percentage and 1.52 goals against average over his last four games, though with only a 2-2-0 record to show for it.
Robin Lehner allowed five goals on 39 shots against Boston, in the goalie's first action after missing New York's previous six games. Lehner was sidelined first with an upper-body injury, and then was kept on the bench due to Thomas Greiss' red-hot play, making it possible that the Islanders will again turn to Greiss against Montreal.
Greiss was named the NHL's First Star of the Week for March 11-17 after posting a .959 save percentage, 1.25 goals against average, and a 3-1-0 record over four games.
One of Greiss' victories was a 2-1 win over the Canadiens on March 14. New York and Montreal have split their previous two meetings this season, with the Canadiens capturing a 4-3 shootout win on November 5.
Islanders forward Cal Clutterbuck also was forced out of Tuesday's game due to an upper-body injury. He is questionable for Thursday.
--Field Level Media